1. Technical Field
The present invention relates to a technique for disposing multiple graphical images in an arrangement within an image region.
2. Related Art
A technique called a “hatching process” is known in the field of image processing. This “hatching process” refers to a process that performs half-tone dot meshing, texturing, and the like by disposing, in an arrangement and with regularity, multiple graphical images within an image region made up of characters, tables, graphics, or the like. For example, Japanese Patent Application No. JP-A-5-210381 discloses a technique that quickly expands a hatching pattern in a frame memory using a BitBlt (Bit-Boundary Block Transfer) circuit that repeatedly transfers block patterns used for hatching rendering into specified regions.
Although the technique disclosed in JP-A-5-210381 is convenient when performing a hatching process on a region of a size that is an integral multiple of the size of the block pattern, it cannot perform an effective hatching process in other cases. For example, even if a hatching process is enabled for regions of arbitrary size by reducing the block pattern to an extremely small size, it is necessary to determine and specify, in detail, the addresses of the regions to which that block pattern is transferred. Therefore, when performing a hatching process on an image that has a complex shape, such as a character or the like, the operations and processing for specifying the transfer destinations of the block pattern become very complicated.
Accordingly, the following technique can be considered for executing, with ease, a hatching process only on image regions of various shapes and sizes. For example, a hatching pattern made up of multiple graphical images arranged with regularity at predetermined intervals is contrasted against an input image on which the hatching process is to be performed; then, only the graphical images located within the rendering region of the input image are extracted from the hatching pattern, and are then disposed in an arrangement in the rendering region of the input image.
However, when a hatching process is performed using such a technique, there are cases where skew occurs between the graphical images contained in the hatching pattern and the rendering region in the input image. In other words, the location of each graphical image in the hatching pattern and the location of the rendering region of the input image are determined independently of each other, and thus there are instances where parts of the graphical images contained in the hatching pattern appear absent at the ends of the rendering region of the input image. When graphical images in the hatching appear absent in this manner, a problem in which the beauty of the hatching, the visibility of the graphical images, and the like are impaired, leading to the degradation of image quality, arises. This problem becomes particularly apparent with hatching that disposes, in an arrangement, graphical images whose overall shape cannot easily be recognized if some of the graphical images are absent, such as star-shaped graphical images, graphical images with a flower motif, and the like.